Improvement in step-ladders



- r v a. eniiNEwALo.

Step-Ladder. I

No, 159,319 Patented Feb.2,1875.

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UNITED STATES PATENT GFFIoE.

GEORGE cEi'inEwALD, OF NEW YORK, n. Y.

IMPROVEMENT IN STEP-LADDERS.

Specification forming part of Letters Patent No. 159,319, dated February 2, 18 75 application filed December 21, 1874.

To all whom it may concern:

Be it known that I, GEORGE .GRiiNEwALn, of the city, county, and State of New York, have invented a new and Improved Step- Ladder, of which the following is a specification:

This invention has for its object so to construct a step-ladder that the same may be used as a scaffolding on stair-cases,&c., and also as a regular continuous ladder.

The invention consists in the new combination and arrangement of parts, hereinafter more fully described.

In the accompanying drawing, Figure 1 is a side View of my improved step-ladder; Fig. 2, a front elevation thereof, showing the bracingladder swung up into'line with the step-ladder. Fig. 3 is a side view of the same in condition as a continuous ladder; Fig. 4, a central vertical section of the ladder transformed into a stair-scaffolding; Fig. 5, a horizontal section on the line 0 c, Fig. 3 5 Fig. 6, a horizontal section on the line It 7c, Fig. 2; and Fig. 7 a detail section through the screw-pivot of the bracing-ladder, the same being shown on an enlarged scale.

Similar letters of reference indicate corresponding parts in all the figures.

The letter A represents the main part of the step-ladder, and B the bracing-ladder or back part thereof. 0 G are a pair of hooks that can be used, as in Fig. 1, to connect the parts A B at the required angle. The stepladder proper, A, is made with diverging side pieces a a, as usual, whereas the bracingaladder B has parallel side pieces I) b, all as clearly indicated in Fig. 2. To the inner faces of the diverging side pieces a a are attached wedge shaped projections d d, which are grooved along their inner parallel faces lengthwise, as clearly shown in Fig. 4., and which serve as guides for the pivots e e of the ladder B. Each of these pivots e e, of which one is more clearly shown in Fig. 7, is a screw that enters through the side piece I), and through the groove of d, into a nut, f, that is sunk into the said piece d.

When it is desired to form the step-ladder into a continuous ladder, such as is shown in Fig. 3, the step-ladder may first be turned up 011 the pivots e e, as indicated in Fig. 2, and the pivot-pins e are unscrewed from the side pieces a, whereupon they drop with the lower end of B along the grooves of d to the lower ends of said grooves, where there are other nuts, f, sunk into the pieces 61, for receiving these pivots in the lower position. Thus it is that a continuous ladder can be formed, as in Fig. 3, by bringing the pivots e to the lower end of the wedge-shaped grooved portions d.

In this position,the side Bars b b of the straight ladder B fit into notches or recesses that are cut into the top plank g of the ladder A, in the manner indicated in Fig. 5, and thereby lock the two ladders properly together without requiring further fastenings.

While the step-ladder is in the position shown in Fig. 1, it may also be swung into the position shown in Fig. 4i-that is to say, the ladder B can be swung at about a right angle to A, and held at such angle by the hooks 0.

1n this position the ladder can be conveniently used on staircases as a scaffolding, the lower end of A standing on some of the steps, while the end of B is rested either on the upper floor or on other steps, and a board then laid over the ladder B will serve as a convenient platform for painters, plasterers, &c.

To enable the lower end of A to stand on a stairs-it being frequently impossible to rest the same on a single step-I have provided an extension-foot, h, for one or both of the side bars a, as shown in Fig. 2. This foot can beapplied, through bands, to either one of the side bars a a, to extend the same as occasion may require.

I claim as my invention The combination of the main ladder A and the diverging side pieces a a with the grooved wedge-shaped attachments d d, the concealed nuts ff, screws e e, and parallel ladder B, all arranged substantially as herein shown and described.

GEORGE GRUNEWALD.

Witnesses:

F. V. BRIESEN, E. O. WEBB. 

